Fluid operated reciprocating piston type windshield wiper motor



Feb- 5, 1952 c. R. sAccHlNl 2,584,229

FLUID OPERATED RECIPROCATING PIsToN TYPE WINDSHIELD WIPER MOTOR FiledMay 27. 1947 2 SHEETS-smeT 2 E E INVENTOR.

A Tron/VE y Patented F eb. 5, 1952 OPERATED. RECIPROCATNG 'PISTON TYPEWINDSHIELD WIPER.l MOTOR Columbus It. Saochini, Willoughby, Qhio..assigner to The. Marquette Metal Products Company@ Qleveland, 011.110,.a corporation of Ohio ApplicatonMay 27, 19471,'Serial- No. 'Z50-,709.-

This invention. relates. t0. all. improyei and simplified fluid operatedmotor of the type shown in e. R. saechini Patent aell., Qotober 5, 1948,thus indicating the generaloblect.;

A further object is to provide alight weight and; eieient. nuidoperated. motor, `the princi-pai parts of which are adapted t0. bellied@lleX- pensively, either as die castings. or Simple Sheet. metalstampings, a concomitantr object being to provide such a motor adapted.and. arranged to. operateA smoothly and quietly by elastic fluid suchasz air.

Another objectv is .tol provide. mirrored .and simpliiied automaticfluid reversing valve and snap. action mechanismtherefor` in conjunctionwith av fluid operated windshield wiper motor- Another object is toprovide an improved and simplified parking Valve device for a windshieldwiper motor, said device being manipulatable to. control the wiperspeed.

A specific object is. to provide aL quietly and posi-tively operatingvalve reversing snap action mechanism for an elastic, iiuid operatedmotor.

Other objects include provision,A inan elasticfluidoperated motor, ofall eXhallSl'. fluid diS- charging muffler operable asa lubricantreservoir for thefiuiol.y reversing valve, and a simple strokeadjustment. device for the power piston of` suchmotor..

Other objectsfand features .of` the invention will; become apparentyfrom the. following description of the preferred form.

In the drawings:

Fig. 1 is aside. elevation of the motor,V designed for operation. byelastic fluid, a. cove-rplate-for acavity enclosing the reversing. valvemechanism. of the motor being broken away as. along thelineL-I of Fig.2.y f

Eig. 2 is` a sectional; View through, thamechaniszn as indicated on Fig.1.

Fig. 3; is a central; longitudinalr section .through themotor asindicatedlon Fig. 2.

Fig. 4 is a fragmentary View Showing Dar-.ts Vthe Supply.- System.including the valves; cach shown. in a. position.. different from.tnatlillustrate@ by: Fig@ .3-

Fig.. 5. is, a detail. @toss sectional.y viewvoi; the speedcontrol and.parking. valve as indicated. on. Fig. 1 and Fig. 6 is a perspective Viewof the reversing sure-,chambers 3;.and 4-.. in;v cooperationwith. a

3 Claims. (Cl. 12b-164);

power piston. 5. and. reversible. cylinder head closure. plates ordiscs. I4. The. power piston.Y also preferably a die casting, hascylindrical disc-like heads 6. rigidly connected by a s .mor rodportion.l having rack teeth 8 formed. thereon- 'lhe rack; teeth, are.. constant.mesh. withy a gear,v sector 9. disuosed within. a :zentralenlargedohainberfiorrning portion ll of the housing dening a Working Space forthe'pistonrod and gear Sector in. open. communioationwith a. lateral.enlargement llo. of saidisuaoe. containing. a snap action togglemechanism. generally des.ig. noted l2 for an. automatioiiuid. reversingvalve plug t3 of. the motor described leterheroin...

'the gear. sector 9, also preferably a dic-cast.- ing, is supported by.a powertalieoir shaftl5. connected therewith as by. a., removable screwthreaded; pin 16... The opposite endsof the. shaft. E15-extend throughrespective bearing formations. IJ of the housing vI, one endY of theshaft being adapted, as by spline serrations itl thereon, to carry awindshield wiper drive arm, (not shown). They other end may have anemergency operating arm I9 pinned thereto in the event of fluid supplylpressure failure.4 The, ami 1 9 isso positioned as to be readilyavailable for manual operation in the mounted, position of thez motorunit. Thevf shaft t5 usually extends. through the. windshieldframework.or an adjacent vehicle bodyl wall, and mounting connections (not shown)are secured to they housing- Ij as usual.

The automatic reversingl valve plug; l3; (Figs.- 2h73., 4. and 6) and..a main fluid control andpark.-

ing, valve plug 2lik (Figs. 3f.. 4, and 5,)r are disposedl in parallelrelationshipI in suitable bores;v 2;! and lgfrespectively. in athckenedbottom portion 2e of the housing lengthwise` thereof atV oneend.

The, reversing valve plug I3. (see. narticularlyA Fig..` fi.)l ispreferably a die. cast.: bodyr cylinder 2.o having a concentricsemi-cylindrical or halfg disc enlargement 26A at. one. end carrying.id.entica1.l integral. abutments 2;? and. 28. projecting-.fromthesupporting half; dziS. in parallel; relationshill to each, otherl andspaced@ apart circumielgen.- tially Vabout the axis.A ot the; plug i3.

The snapy action toggle mechanism.. lf2 (Figs. 11 and 2), isv disposedin the chamber Ha.y denedzA in part by a continuous housing` Wall 3D,Fig. l, complemented. byv a readilyremovable .cover plate 3L which isthesole supportforthe toggle mech.- anism. anad may be. secured tothe-wall Sil-.as by.V screws 32;. The toggley mechanism comprises. a.motor-actuated toggle.y arm, .33.. and; a valyeactuating. toggle. arm. 34. both, adzuol'ecl` Vtu. he.. made.;

as nearly identical sheet metal U-shaped parts.

. At least two toggle arm portions (35 and 36 as shown) are pivotallysecured together and to the cover plate 3I as by a non-binding rivet 31passing through said arm portions and the cover plate. As shown theremaining arm portions 39 and 40 are also pivotally connected by anon-binding rivet 4I having no support other than that afforded by thetoggle arms. End indented or crotch portions 42 of the toggle armssupport respective eye formations of a coiled tension spring' 43 whichtends to maintain the arms in disaligned or snapped-over relationship(one such position illustrated in Fig. 1) at opposite sides of theiraligned or dead center positions with respect to the connecting pivots31 and 4I.

To operate the toggle mechanism, the piston stem or rod portion 1 hasintegrally formed thereon abutment shoulders 44 and 45 (Figs. l, 2 and3) positioned for engagement with opposite edges of the toggle armportion 39 (see Fig. 2) during movement of the piston in respectivelyopposite directions.

To limit the throw of the motor operated toggle arm 33 and to arrestsaid arm without impact noise, the cover 3I carries and/or retains inposition abutment blocks or stops 46 and 41 0I elastic material such assynthetic rubber disposed in the path of the toggle arm and which, asshown by Fig. 1, are laterally supported by respective opposite innerwall surfaces of the wall 30 of the chamber II a. The cushion blocks, asshown, are generally cylindrical and necked between their ends forsupport in openings (not shown) in the cover plate 3l, the plugs beingsnugly force-fitted into the openings.

The valve actuating toggle arm 34, in each arrested position of thetoggle mechanism, extends, with approximately Zero clearance (see Fig.1), between the abutments 21 and 28 of the valve plug I3 and is forcedby the spring 43 alternately against those abutments to turn the valveplug from one position of rest to the other. When the toggle arm 34 hasturned the plug through the necessary angle (e. g. 60 degrees) toreverse introduction and exhaust of pressure fluid in respect to thepressure chambers 3 and 4, said arm is brought smoothly to rest inengagement with respectively different face portions of the abutments aswill be evident from inspection of Fig. 1. Each abutment 21 and 28 has arounded face portion 48 engaged by one edge of the inner toggle armportion 40 as that same arm portion engages a flat face 49 on the otherabutment in the arrested, zero moment arm, position of the toggle arm34.

When the toggle arms, by operation of the piston 5, are brought intodead center alignment, the arm 33 usually snaps into engagement with oneof the cushioned stops 46 or 41 and the contracting spring 43 then jerksthe valve plug to reversed position by action of the toggle arm 34 onthe appropriate one of the rounded abutment faces 48. Because there issubstantially no clearance between the toggle arm 34 and either abutment21 or 23 in each arrested position of the toggle mechanism, there is noclicking noise accompanying valve reversing movements of the valveactuating toggle arm.

The supply duct-system for operating fluid is entirely illustrated inFigs. 3 and 4 and, essentially, is the system shown in U. S. Patent2,450,564. A threaded inlet 50 leads the operating uid through a smallbore I to the parking and control valve bore '22 past the latter at 52 4to a vertical short bore 53 intersecting the reversing valve bore 2l.The reversing valve plug portion 25 has a. manifold cavity 54 which isalways in communication with the bores 52 and 53. Alternately actingcavities 55 and 56 generally opposite the cavity 53 and in thetransverse plane thereof are connected with the manifold cavity 53 byidentical oblique bores 55a and 56a in the plug body. The cavity 55 inthe position of the plug I3 illustrated in Fig. 4 opens the supplypressure source to communication withva bore 58 leading to the pressurechamber -3. In the position of the plug I3 illustrated in Fig. 3 thecavity 56 opens the pressure source to communication with a bore 60, acontinuation 6I thereof beyond the control valve bore 22 and a branch 62of said bore 6I for communication with the pressure chamber 4.

In the positions of thevarious parts illustrated in Fig. 3, the pistonwill immediately begin moving to the left reversing the position of thevalve plug I3 (see Fig. 4) at the end of the leftward piston stroke,thus re-initiating a piston stroke to the right.

As the piston moves to the left from the position illustrated in Fig. 3,spent fluid is forced from the pressure chamber 3 through the bore 58 toone of a pair of relatively obliquely positioned radial bores 64, 65 ofthe Valve plug I3 communicating at their inner ends with a common axialexhaust bore 66 formed in the valve plug. The outer end of the exhaustbore 66 opens into a muiler chamber 61, Fig. 2, containingfluid-pervious, sound-deadening material such as felt which also servesto retain lubricating oil to supply the complementary surfaces of thevalve plug and its receiving bore therewith. The felt is contained in acup-shaped retainer 68, having a central exhaust fluid outlet hole 69.

The'body 2D of the speed control and parking valve is generallycylindrical as shown by comparison of Figs. 3 and 4, one end having anoncircular reduced portion 10 entering a complementary non-circularopening in a sheet metal operating arm 1I by which the control andparking valve may be turned from its illustrated full on position, Fig.3, through gradually restricting uid supply positions to the full off orparking position, Fig. 4, further denoted by the broken line showing ofthe arm 1I in Fig. l. The arm 1I has a stop finger 12 struck therefromfor engagement with the bottom portion 24 of the housing in the full onand full off positions.

The valve plug 26 is secured in the bore 22 by a screw or bolt 15, theself-locking nut 16 of which forces a spring washer assembly 11, 18against said portion 24 of the housing frictionally to hold the valve inadjusted position. The free end of the arm 1I has an opening 19 forattachment of an operating rod or link in the event the installation issuch that the arm 1I cannot conveniently be reached by the operator ofthe vehicle served by the wiper motor.

The operation of the valve plug 20, etc. for parking (assuming the plughas lbeen turned to the Fig. 4 position so that the diametrally oppositerecesses and BI are vertical and assuming further that the reversingvalve plug I3 is still in the Fig. 3 position) is as follows: Fluidentering the bore 5I flows upwardly through the recess 80 directly tothe bore 6I, thus by-passing the automatic reversing valve plug I3. Thatdrives the power piston 5 to the left (Fig. 3) to the end of its stroke.reversing the position of the valve plug I3. enroute. through theintermediary of the toggle mechanism. In the meantime (still assumingthe valve plug I3 is in the Fig. 3 position) exhaust uid leaves thepressure chamber 3 as already described. If the piston 5.

is moving toward the right (before tripping the toggle mechanism) at thetime the parking end and control valve plug 20 is turned to parkingposition, then (see Fig. 4) the pressure c h a m through the cavity 55,oblique passage 55a, and manifold cavity 54 of the plug I3,ibores 53,52, recess 8l of plug 20, bore portion 60 and radial bore 65 of the plugI3.

The arrangement for enabling, selectively, long and short strokeoperation of the power piston is shown in `Figs. 2 and 3. Those figuresshow, partly in dotted lines, additional togglemechanism-operatingabutments at |44 and |45 spaced less wide apart than the` abutments 44and 45 so that the toggle mechanism is tripped or moved past its deadcenter positions at shorter intervals in respect to the travel of thepiston at a given speed. Adjustment of the mechanism for long and shortstroke operation requires simply removal of the cylinder heads I4 and acover plate |00 (so that the gear sector 9 may be removed) and thenremoval and reversal of the piston end for end and side for side.Concernitantly the cylinder heads I4 are reversed in position inaccordance with the change, whether for long or short stroke, so thatpiston abutting embossed portions Ilia on the cylinder heads are eitherturned outwardly as illustrated in full lines or inwardly as partiallyillustrated in broken lines at Ida. The embossed abutments Ma engagereadily removable impact-cushioning and sealing discs 82 of elasticmaterial which are expanded over anged projections 83 integral with thepiston casting to limit the tendency for the piston to overtravel to anundesirable extent at high operating speeds of the motor. The two setsof abutments 44, 45 and I44, |45 have a further advantage in that theybalance the piston against tending to rotate out oi' operating positionin the cylinder bores (see Fig. 2).

Incidentally, by reason of the inherent tendency for the piston toovertravel when elastic uid is used to operate the motor, the reversiblepiston heads I4 may be used in some cases roughly to control or adjustthe length of wiper stroke at high speeds without having to reverse thepiston. In that case, one of the cylinder heads may be left in its fullline illustrated position and the other reversed to the broken lineillustrated position, whereby the piston will bevenfr abled to movefarther from mid position in one direction than in the other.

I claim: 1. A reciprocating fluid operated motor com- I prising a casinghaving opposed cylinders, a

the exhaust uid fromL ber 3 leaves the bore 58v piston spaced apartlongitudinally thereof for operating the reversing valve means, and morewidelyspaced abutments on the opposite side of said rod portion forlonger-piston-stroke operation of the valve means in an end-for-endreversed position of the piston in the cylinders.

2. A snap action toggle mechanism for a fluid operated motor of the typehaving a reciprocatable piston means and a rotatable valve means forcontrolling the operation of the piston means, said mechanism includingspring-oonnected coaxially pivoted toggle arms operativelyinterconnecting said valve means and said piston for driving said valvemeans with alternate rotary motion upon reciprocation of said piston,one of the toggle arms acting against circumferentially spaced abutmentson the rotary valve means to turn the latter, said one toggle arm andthe abutments moving in counter-directional arcuate paths aboutdifferent centers and the abutments and arm having complementary facesbrought gradually into full face-to-face arresting contact at regionslying on both sides o'f a line perpendicuar to said faces and passingthrough the turning center of the valve, the clearance between thetoggle arm and both of the abutments being approximately zero in eacharresting position of the toggle arm and valve.

3. In a duid pressure operated reciprocating motor, having opposedpressure chambers, a fiuid supp-ly duct, automatic valve means in saidduct for alternately supplying pressure fluid therefrom to the chambers,and a parking valve including a valve bore intersecting and interruptingthe supply duct and one of the feed ducts, said plug havingnon-communicating radially open valving recesses on diametrally oppositesides operable in one position of the plug to establish supply fluidconnections to the automatic valve means and from the automatic valvemeans to said one of the chambers and operable in the other position toblock iiuid ow to and from the automatic valve means and simultaneouslyrender portions of the ducts effective to supply operating fluid to saidone of the chambers for parking.

COLUMBUS R. SACCHINI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 473,296 VGreat Britain Oct. 11, 1937

